Which of the following is the preferred site for injecting medication to ensure rapid action and minimize side effects?

The acceleration due to gravity on the moon is $\left(\frac{1}{6}\right)$ times the acceleration due to gravity on the earth. If the ratio of the density of the earth $\rho_{e}$ to the density of the moon $\rho_{m}$ is $\frac{5}{3}$,then the radius of the moon $R_{m}$ in terms of the radius of the earth $R_{e}$ is:

$A$ pendulum suspended from the ceiling of a train oscillates with a time period $2\,s$,when the train is accelerating at $10\,m/s^2$. What will be its time period when the train retards at $10\,m/s^2$?

When a ceiling fan is switched off,its angular velocity falls to half while it makes $36$ rotations. How many more rotations will it make before coming to rest? (Assume uniform angular retardation)

Integrated Pest Management $(IPM)$ is based on which of the following?

The $Adaptation$ of eyes in the dark is due to